Ken Pomeroy Has Written About Fouling Up Three, and He Says Defend

Ken Pomeroy has finally come out with a study on fouling when up by 3 points late in a game, or defending, something we have seen again this weekend with the crazy Wisconsin-Michigan finish. I wrote about it a couple of weeks ago, and my general takeaway was that I would not go hard line on either position, and would take specific factors (rebounding, opponent outside shooting, the fouled players free throw ability) into account, but the default would be more likely foul than defend.

The fact is, chances of losing are close to remote in either case, but execution errors, an inflated offensive rebounding percentage, poor three-point shooting, and the chance of an extra possession are enough to counteract what might otherwise be the advantage of forcing a team to shoot free throws. In cases where the opponent has multiple good three-point shooters and you have confidence in rebounding a missed free throw, fouling may be the better option. But it appears the default decision should be to not foul.

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To me, the only conclusion one can make is that the criticism of coaches that choose to defend appears to be misplaced. A small percentage of the time you’ll get burned no matter what you choose to do. We will continue to see teams make game-tying threes near the end of games more often than they get fouled simply because more coaches choose this strategy. In the long run, it’s difficult to prove it’s a bad idea.

I think there is a lot of value here, and he went through actual game scenarios from the last four seasons. His final results:

If you count overtimes as half-wins, the percentages work out to 92.7% for the Foulers, and 94.0% for the Defenders.

I still think my default would be to foul, but vary based on game situations. I’ll point out a few things, just like Pomeroy did. The sample sizes of failures aren’t going to be enough to definitively say for awhile.

Okay, so let’s start with this. There are three Fouling Fails that went to overtime that could be classified as Defends, since the opponent hit a buzzer beating three to tie. Two involved the foul forcing a missed free throw, and a defensive rebound, and a foul to force the leading team to hit again. In both cases, the team with the lead regained the 3 point advantage, only to give up a buzzer beating 3. The craziest was a UALR-Denver game in 2011, where it was just in the stars, and both long shot strategies failed in the same game. First, the player got a shot up while an intentional foul occurred. Then, Denver extended it back to a 3 point lead after the UALR free throw shooter made 2 of 3, only to have a buzzer beater tie it.

Pomeroy is counting those against the Foul strategy. If we swap those to Defend situations (certainly arguable since the team chose to defend given another chance), the numbers are virtually identical for success rate.

Now, look at what happened on the rare occasions when a three point shot was fouled, either by a team trying to defend straight up, or a team trying to commit an intentional foul but doing it too late.

There are a lot of things we have to guess on, when it comes to what is luck or repeatable. I’m going out on a limb, though, and saying there is nothing special to someone being fouled on a three while it was intentional vs. an attempt at a block, when it comes to forcing overtime. Free throws are free throws. A 70% shooter should make all three to tie it about 35% of the time. Instead, both intentional foulers went to overtime, while most of the unintentional foulers survived. Flip the luck, just on those 13 outcomes where a team fouled a three point shooter, and fouling intentionally looks like the (slightly) better strategy.

The interesting thing I found is the offensive rebound rates on missed free throws. Pomeroy has it at 39 of 96 (40.6%) for teams getting an offensive board off the missed free throw. If that rate were to hold up over a larger sample size, it would make the two strategies roughly equal. If the real rate over a very large sample is 30%, though, then fouling is better. That rate corresponds to roughly the rebound rate on missed two point shots, which in many situations have offensive players in far more favorable rebounding positions, some of which come from the shooter putting back his own miss. My feeling, even with the rebounders crashing, is that the rate isn’t going to be higher, and could be lower.

I would still use the default to foul, and I think that the luck in a few free throw situations after fouled threes, a crazy Chandler Parsons three quarter court shot (way less likely than what Brust did, and with a far smaller sample size of comparable events), and a slightly improved defensive rebound rate swing the math going forward over time.

That said, I agree that the Brust shot is not the best example of when to foul, as he had to heave a desperation attempt. The better time is when the opponent will have just enough time to set up a screen or make an extra pass to a shooter. That was bad luck. I still think, though, that though neither strategy is clearly far superior, more than 10% of coaches should be trying the foul strategy. The most important factors to consider are time remaining, likely rebound success rate based on matchup, the shooters for the opponent and likelihood of getting more than a desperation heave under pressure, and foul shooting ability of opponent.